Tridimensional radio compass



June 30, 1925.

c. c. CULVER TRIDIMENSIONAL RADIOCOMFASS Filed June 29, 1921 4 sheets-sheet 1 June 30, 1925. 1,544,133

v c. c. CULVER TRIDIMENSIONAL RADOCOMPASS Filed June 29, 1921 `4 Sheets-Sheet 2 Smc/whom June 30, 1792.5. 1,544,133

c. c. cULvER TRIDIMENS IONAL RADI @COMPASS Filed June 29, 1921 -4 Sheets-Sheet 5 June 30, 1925. 1,544,133

c. c. cULvER ITRDIMENS IONAL RADI OCOMPAS S Filed June 29, 1921 4 Sheets-Sheet 4 Patented June 30, 1925.

UNITED STATES PATENT OFFICE.

CLARENCE C. CULVER, 0F WASHINGTON, DISTRICT O'F COLUMBIA.

TRIDIMENSIONAI. RADIO COMPASS.

Application iiled June 29, 1921. Serial No. 481,421.

-` j This invention relates to methods of appreaching a landing-station by sending out radio signals, and in particular has .for one of its objects a system of radio compass loops that permits ofstationary adjustments of such loops for varying conditions of loading on an airplane.

In a companion case I outlined a skew method of fixedly adjusting a single coil radio compass so that the proper spiralling angle of descent can be obtained for a. given airplane and for a given loading of the same. The single coil method, however, has its manifest disadvantages whereas it is a feature of the present invention to variably adjust a series of fixed coils so that in case of a forced landing at an intermediate landing station the proper spiralling angle can be obtained taking into account any reduction in lballast as might occur in a postal route or the like. Especially is this desirable where in a long flight the gasolene consumption may be very great and therefore with every change of balance or load a new spiralling angle is actually necessary, or at least desirable. A further feature of the invention, therefore, is a system of coils which not only gives the necessary component having the desired athwart angle, but which system is also capable of giving any desired nosing angle.

In order better to disclose the nature of my invention I have annexed herewith the' accompanying drawings, in which:

Figure 1 represents a diagrammatic view of the spiralling path taken by an airplane with respect tothe cone of radiation enia' nating from a signaling source;

Figure 2 diagrammatically represents an arrangement of radio compass coils to give the component effect of spiral plane flying.

Figure 3 indicates a schematic arrangement for leading the energy of the radio compass coils to a common receiver circuit. Figure i diagrammatically represents an arrangement of radio compass coils to give the. component eect of cylindrical or helical flying.

Figure 5 corresponds to a schematic arrangement similar to Figure 3.

Figure 6 illustrates the manner of combining both types of radio compass coils to give the combined effect of conical ying.

Figure 7 corresponds to the combined schematic arrangements of Figures 3 and 5.

Figure 8a represents dia-grammatically an y end view of the coil arrangement for the cylindrical iying component.

Figure 8b is a perspective view corresponding to Figure 8a. i

Figure 8c corresponds to a plan view of Figure 8a showing the apparent trace of the resultant coil for cylindrical iiying.

Figure 9 represents diagrammatically a plan view of the coil arrangements for plane spiral iiying.

Figure 10 schematically represents the apparent resultant trace of the combined resultant coils for cylindrical and plane spiral flying.

Figure 11 corresponds to an end view of the resultant trace of Figure 9.

Figure 12 corresponds to a side view of the resultant trace of Figures 10 and 11.

Referring to Figure 1 a source O on the ground of the landing field or station sends out electromagnetic waves of which the circles H correspond to the trace of the lines of magnetic force. An airplane P reaching the vicinity of the landing field would as a first step circle about the station, making the longitudinal axis of the plane a tangent substantially to the magnetic circles I-I at a given height from the ground. The general direction of the center O of Such circle can be determined by suitably arranging the turns M and M1 of two coils ABCD and abcd, which latter are angularly disposed with regard to the athwart axis of the plane. Naturally with the two coils just mentioned v'symmetrically arranged, the number of turns employed with respect to a receiving or indicating coil m of a telephone circuit T would be equal. However, if the common line AD,ad is not midway between Bb or Cc the proper proportion of turns will effect the 'desired result. Similarly, if a common line DC or d'0. of the two coils ABCD, abc'd, is em loyed for the samepurpose (see Figure 4 the respective number of l'turns in M or M1 can be properl chosen to give the desired effect in t e common ieceiving coil m. Obviously all four coils MM1MM1 can be arranged to act together on the receiving circuit T as indicated in Figure 7. l

Having achieved the condition of circular' flying, as indicated by the position P in Figure l, it is obvious that the angle of the plane of the resultant compass coil effects, with respect to the longitudinal axis of the plane, should be so arranged that the. airplane will take up some such position as P in order that with the proper nos'ing of the plane and proper banking the plane vwill reach the ground of the ield along-the path of a conical spiral such as S of the gure. Obviously if the radio compass coil has been properly oriented with respect to the airplane, and the airplane properly oriented for conical flying, the angular displacement 0 of the result-ant coil with respect to the longitudinal axis of the plane will be eX- actly allowed for by the correcting displacement 6 of the airplane axis. In this Way, in the conical flying achieved, the plane of the resultant compass coil will always be perpendicular to the circular lines of diverging magnetic intensity H. The signals will then, and then only, become increasingly stronger and the aviator will know that he is continually approaching the source of radio energy at the proper descent angle. 7

The proper descent angle 0 is in general made up of two components, the nosing angle 0 and the proper banking angle 0b. However, the effect of travel of the airplane can also be said to result from a plane spiralling component (excess banking and no nosing) and a' cylindrical helical component (nosing efl'ect per se) with just suiicient banking to keep the cylindrical 'radius-constant. Q Each. deviation of the airplane axis, and consequently the deviation of the radio compass coils carried by the airplane, needs aconsequent correction. For clarity, therefore, the above two components will be considered separately.

Turning to Figure 4 "it will be assumed that the cylindrical radius of Hight is maintained substantially constant and that no nosing effect is introduced. Under these circumstances the two coils ABCD, a'bcd can be employed by varying the turns MM, of the usual coupling coils with respect to a receiver circuit mT that the effective resultant of the two coils is'equivalent to a coil substantially perpendicular to the longitudinal axis of the plane. If, now, cylindrical helical flying is to be resorted to, by properly nosing the lplane downwardly, the revious adjustment will require modication so as to keep the'plane of the resultant coil previously referred to in substan- -indicated in Figure 1.

tially the saine cutting plane with respect to the H-lines of radiation as before. The consequence will be that by proper adjustment of the turns M and M1 a resultant position, such as that indicated in Figure 8a will be obtained. In plane circular flying the trace a-a of Figure 8c would coincide with the athwart axis OO.

In view of the fact, however, that a conical iiying effect is desired, the ba-nklng of the plane would have to be such that the longitudinal axis of the plane should never be tangent to the circles of H, but in fact should be tangent to the conical spiral part Thus superposed upon the effective resultant coil arranged forby means of the two component coils illustrated in Figure 4, there Will be required a second resultant coil whose athwart axis makes an angle with the line DCdc of Figure 4. In this way the excess of banking effort to make. the plane continually apprrich the radio source can be corrected for.

Y of Figure 2, the above result can be achieved by suitably varying the turns of the cou lings M and M see Figure 3). Clear y, if an excess of banking is to he introduced to provide a spiralling effect, the respective coupling should be such that the trace of the resultant coil giving the spiralling component should be as indicated by Dd---Dld1 in Figure 9. 1

Combining, therefore, the two resultant coils of Figures 8 and 9 by having all four coupling coils MM,MM1 (see Figure 7) act upon the common receiver circuit mT,

the combined trace of the final resultant coil will be as indicated inplan in Figure 10, in end view as in Figure l1, and in side view as in Figure 12. The actual effective position of the final resultant radio compass coil will therefore have as its limiting componental positions either the resultant position of Figures 8, 8, or Figure 9, depending upon the preponderance of coupling of the set MM,L as against MMl. The two'sets of coils are shown in assembly in Figure 6.A

In operation, in a proaching a landing field the settings `of tiie coupling coils MM1 MMl are made such that the radiation is substantially received athwart the airplane. Thereafter, depending rupon the type of airplane and the loading of the same the coupling members are set to give an effective trace of a combined resultant radio compass coil that is oblique to both axes of the airplane. The banking and nosing of the plane can be so regulated as to correspond with the setting for the combined resultant coil which manipulation of the airplane controls will then give maximum intensity of signal coupled with the effect of increasing intensity in the signals produced. By such a process as outlined above, the airplane will means of the coil ABCD and abcd radio compass havin `form ai plurality of then always approach the landing field automatically in best position.

What is claimed is:

1. In combination with an airplane, a -a pluralit of coils to hedral angles, the axes of said dihedral angles being angularly disposed With respect to each other and to the longitudinal axis of said airplane.

2. In combination with an airplane, a radio compass having a plurality of coils to form a plurality of dihedral angles, the axes of said dihedral angles being angularly disposed With respect to each otheixand to one of the axes of said airplane.

3. In combination with an airplane, a'-

radio compass-comprising two sets of coils forming dihedral angles,vthe axes of said dihedral angles being angularly disposed with respect to eachother and with respect to an axis of the airplane,and means for variably affecting the eii'ectiveness of said sets of coils individually with respect to`each other.

. 4. In combination With an airplane, a

radio compass comprising three coils, the

axes of said coils angularly'disposed to form a solid angle, means to produce a single resultant from said coils and further means `for variably affecting the direction of said resultant with respect to the axes of said airplane.

In testimony whereof I aiix m si ature. l CLARENCE` C. CITLIER. 

